Double acting diaphragm pump



2 Sheets-Sheet 1 F. R. SMITH DOUBLE ACTING DIAPHRAGM PUMP;

Feb. 3, 1959 Filed Fab. 29, 1956 I I I'll Feb. 3, 1959 F. R. SMITHDOUBLE ACTING DIAPHRAGM PUMP 2 Sheets-Sheet 2 Fil ed Feb. 29, 1956United States Patent O DOUBLE ACTING DIAPHRAGM PUMP Frederick R. Smith,Nitro, W. Va., assignor to American Viscose Corporation, Philadelphia,Pa., a corporation of Delaware Application February 29, 1956, Serial No.568,522

13 Claims. 01. 103-150 The invention relates to pumps, and particularlyto double acting diaphragm pumps.

An object of the invention is to provide a generally improved and moresatisfactory double acting diaphragm pump.

Another object is the provision of a pump of small physical dimensionswhich is simple in construction and operation and employs a minimum ofmoving parts which are not subject to rapid wear or corrosion.

Still another object is to provide a pump, particularly suited for usewith sensitive instruments such as laboratory test equipment, which iscapable of delivering small amounts of fluid at a relatively accuraterate.

A further object is the provision of a double acting diaphragm pump inwhich the diaphragm actuating lever is enclosed within and forms a partof the diaphragm itself, and the fluid flow control means includeresilient flap valves.

A still further object is to provide a pump formed of a series of partssecured in juxtaposed relationship for ease of manufacture, assembly,and repair.

These and other objects and advantages of the inven- I tion will beapparent from the following description and accompanying drawing inwhich:

Figure l is a perspective view illustrating part of the structure in anexploded position, and with a portion thereof being broken away;

Figure 2 is a front view of structure shown in Figure 1 in its assembledposition;

Figure 3 is a left side view of the assembled structure shown in Figure2;

Figure 4 is a fragmentary detail illustrating the operation of one ofthe pump flap valves; and

Figure 5 is a view similar to Figure 3 illustrating a modified form ofdiaphragm actuating lever.

In general, the invention relates to a double acting diaphragm pumpformed of a plurality of parts individually fabricated and then securedtogether in juxtaposed relationship. The diaphragm actuating lever isenclosed within and forms a part of the diaphragm itself, and extendsoutwardly of the pump body where it is accessible for reciprocatingmovement. rial are employed to control the rate and direction of fluidflow. The pump has particular utility with test instruments whererelatively small and accurate fluid delivery rates are desired, and thevarious parts maybe formed of inert materials when use of the pump withcorrosive fluids is anticipated. a

The pump of the present invention is formed of a plurality of blocks orplates and sheets disposed in juxtaposed position and secured togetherto form an integral unit which is, in effect, two independent pump unitsactuated by a single diaphragm interposed therebetween. Thecorresponding parts on opposite sides of the diaphragm are mirror imagesof each other, and for the sake of clarity and simplicity, thedescription will be in general limited to the diaphragm and the parts toone side thereof, it being understood that parts on the opposite Flapvalves of resilient mateto flow only toward the pump chamber.

2,871,795 Patented Feb. 3, 1959 "ice ' 2 side of the diaphragm are ofthe same construction as those parts which are described hereinafter.

With reference to Figures 1-4 of the drawing, the diaphragm 7 is formedof two sheets of flexible material 9' posed therebetween, while theremaining portion of the.

actuating lever 13 projects outwardly from the edge of the diaphragm inan accessible position for reciprocation as hereinafter described. Asbest seen in Figures 1 and 3, the end of the actuating lever interposedbetween the sheets 9 and 11 is formed into a ring 15 which is positionedapproximately centrally of the diaphragm so that the force exerted byreciprocating the actuating lever is transferred to and distributedalong a substantial area of the diaphragm. Against opposite faces of thediaphragm 7 are disposed the chamber blocks 17, each having its centralportion formed with a circular opening 19 which serves as a pumpchamber. The edges of the chamber blocks 17, adjacent the projectingportion of the actuating lever 13, are each formed with a tapered recess21 which gradually decreases in dimension as it approaches the centralopening 19. As shown in Figure l, the recesses 21 terminate beforereaching the central opening 19 in the chamber blocks, and thus thesegments 23 of the chamber blocks located between the central openings19 and the innermost ends of the recesses 21 together serve as a fulcrumfor the actuating lever 13.

Continuing the description'in relation to one of the pump units, againstthe face of the chamber block 17, opposite the diaphragm 7, ispositioned a rectangular block 25, which for convenience may be called afluid passage block. The top edge of the block 25 is formed with anoutlet port 27 and an inlet port 29 which connect, respectively, with'the angulated outlet passage 31 and the inlet passage 33, both of whichopen on the face of the block 25 remote from the chamber block 17. Anoutlet channel 35 passes transversely and angularly through the block 25with its lowermost end opening into the pump chamber opening 19. Thischannel allows gas bubbles to escape from the pump chamber and alsoserves as a means for discharging the fluid therefrom. Delivery of fiuidinto the pump chamber is accomplished through an inlet channel 37passing transversely through the block 25 and opening into the pumpchamber 19 as best seen in Figure 2.

Control of the rate and direction of fluid flow is accomplished by flapvalves formed by means of a flexible and resilient sheet 39, preferablyof rubber. The sheet 39 is disposed against the outermost face of theblock 25 and is provided with two semi-circular openings 41 and 43 whichare, respectively, in alignment with the outlet passage 31 and the inletchannel 37. The portion directly below the opening 41 serves as a flapvalve 45 which covers the end of the outlet channel 35 and prevents thepassage of fluid therein while allowing fluid to freely flow therefrom.In a similar manner, the portion directly opposite the opening 43 servesas a flap valve 47 which covers the end of the inlet passage 33 so as toallow fluid A valve plate 49 is disposed against the sheet 39 and isprovided with a pair of circular openings 51 and 53, which are in alignment with the openings 41 and 43 formed in the sheet 39 and provide anarea Within which the resilient portions 45 and 47 of the sheet 39 canflex as hereinafter described. An end plate 55 is disposed against theface of the valve plate 49 and serves to close the openings 51 and 53.It is of course understood that the plate 49 may be of sufficientthickness so that the openings 51 and 53 may extend partially into theplate 49 and thus be closed at the end opposite the sheet 39. In thismanner the end plate 55 may be entirely eliminated.

The various parts described above are assembled as shown-in Figure landmay-{be secured together by means of elongated screws 57 passing throughsuitableopenings 61 formed in the various parts and flxedin place 'bynuts 59, or maybe adhesively bonded together for ease of .construction.

As with conventionaldiaphragm pumps, the reciprocation of the actuatinglever causes the diaphragm to induce a suction force anda pressure forcein each of the pump chambers in an alternating relationship. Further, ina double acting diaphragm pump, the-suction and pressure forces in the.two individual pump units are also in alternate timed relationship.since the movement of the diaphragm in one direction creates .a suctionforce in one pump unit and a pressure force .in the other of the pumpunits, while a movement-.ofthe diaphragm in the opposite directionreverses the forces .induced in the respective pump units. Thus inoperation, fluid is admitted through the inlet port 29 and passes intothe inlet passage 33 where its flow is obstructed by .the resilient flapvalve 47 of the sheet 39. As the actuating lever 13 is reciprocated in ahorizontal direction, the suction created with each reciprocating strokeof the lever 13 causes the flap valves 47 of the respective pump unitsto be flexed away from the ends of the inlet passages 33 in an alternaterelationship'so as to allow the fluid to pass through the inlet channels37 and finally into the pump chambers 19. Any gas bubbles contained inthe fluid rise to the top of the chamber 19 and are free to escape intothe outlet channel 35 and finally through the outlet passage 31 and port27.

The pressure force induced by the reciprocating diaphragm is exerted onthe .fluid contained within the respective pump chambers and moves thefluid upwardly into the outlet channel 35 thereby causing the flap valve45 to flex away fromthe block 25, as best seen in Figure 4, so as toopen the end of the outlet passage 35 and provide an unobstructed pathfor the fluid thereto. Thus, as the free end of the actuating lever 13is reciprocated to the left, as viewed in Figure 1, the diaphragm bulgesinto the right pump unit and the flap valve 47 of the left pump unit isurged away from the end of the inlet passage 33 allowing fluid to flowfrom the passage 33 downwardly into the inlet channel 37, as shown bythe arrow in Figure l, and finally into the left pump chamber 19. Thesuction created by this reciprocating move ment tends to draw the flapvalve 45 of the left pump unit more snugly into engagement with the endof the outlet channel 35 thus preventing any fluid in the outlet passage31 and the valve opening 51 from moving downwardly into the left pumpchamber. While a suction force is induced in the left pump unit of thestructure shown in Figure l, the diaphragm causes the fluid in the rightpump chamber to be subjected to a pressure force urging the ,fluidupwardly into the outlet channel 35 of the right pump unit, causing theflap valve 45 to flex away from the block 25, and allowing the fluid topass freely into the passage 31 from which it can be withdrawn to asuitable conduit placed within the outlet port 27. It is seen thatcontinuing the reciprocating movements of the actuating leveralternately cause the diaphragm 7 to pull or draw fluid .into one of thepump chambers while simultaneously causing an equal amount of fluid tobe discharged from the other of the pump chambers.

It is evident that the stroke of the actuating lever 13 and the rate ofreciprocation can be varied to control the rate of fluid flow. Furthercontrol of the fluid flow can be obtained by designing the valves 45 and47 so that they flex to a certain degree when subjected to a specificsuction or pressure force. This latter control can be accomplished byemploying sheets 39 of certain desired thicknesses .and resiliency.

With reference to Figure 5, the modified diaphragm actuating lever 65has its fulcrum or axis, indicated by the broken line 67, lying in aplane tangent to the openings forming the chambers 19. The innermost endof the lever 65 is formed with a substantially right angled portion 69and a ring 71 which together are secured between the pair of flexiblesheets 'formingthe diaphragm 7, while its outermost'end is provided withan arm 73 to which a reciprocating movement can be applied by anysuitable means, not shown. Preferably, the central portion 75 of thelever 65 is not bonded *to the sheets'forming the diaphragm. Theremainder of the pump structure shown in Figure 5 is thesame asdescribed in regard to Figures 1-4. It will be noted that taperedrecesses 21, as provided in the structure shown in Figures 1-4, are notnecessary when theinodified diaphragm actuating lever is employed.However, the chamber blocks 17 are provided with corresponding arcuatevgrooves, not shown, which together cooperate to form a passage for thecentral portion 75 of the lever 65.

The operation .of .this modified pump arrangement is substantially thesame as explained above in regard to the structure shown inFigures 1-4,except that the actuatinglever 65 pivotsabout its axis -67 as areciprocating movement is applied to the arm 73. The portion 69 and ring71 of the lever 65 thereby cause the diaphragm to alternately bulge .inone direction and then the other to sequentially draw fluid into one ofthe pump units while simultaneously discharging an equal amount from theother of the pump units.

From the above description, it is seen that the various plates orblocksand sheets can be easily fabricated independently onanindividual basiswith conventional equipment and'methods and that the parts, oncefabricated, can be assembled without the use of any special skills orequipment. Further, the-parts can be madefrom chemically inert materialsto eliminate any corrosion problems. The physical dimension of the pumpsand their ability to deliver fluid in accurate amounts particularlysuits them for use in laboratory work. Pumps have been constructed inaccordance with the present invention which are 2 inches by 2 inches by1 /8 inches and which deliver milliliters (ml.) of fluid per minute whendriven at .12 revolutions per minute (R. P. M.). Smaller size pumps 1%,inches by 1% inches by 1% inches have also performed satisfactorily andare capable of delivering approximately 3.75 ml. per minute when drivenat 12 R. 'P. M. with a inch stroke and 5 ml. when driven atapproximately 4 R. P. M. with a /2 inch stroke. These pump dimensionsare merely given as examples and of course not intended to be construedas limitations on the scope of the invention.

It is seen from the above description that the objects of the inventionare well fulfilled by the structure described. The description isintended to be illustrative only and it is to be understood that changesand variations 7 may be made without departing from the spirit and scopeof the invention as defined by the appended claims.

I claim:

1. A double acting diaphragm pump having a pair of opposed pumpchambers, a flexible diaphragm disposed between and separating said pairof opposed pump chambers, diaphragm actuating means connected in contactrelation to said diaphragm and extending laterally therefrom, inlet andoutlet means facilitating fluid flow into and from said pump chambers inresponse to movement of said diaphragm, and valve means for controllingthe fluid flow through said inlet and outlet means.

2. A construction as defined in claim 1 wherein said actuating meansincludes a lever and said diaphragm includes two sheets of flexiblematerial secured to each other in contact relation, with a portion ofthe lever interposed therebetween.

3. A construction as defined in claim '2 wherein said lever extendsoutwardly from said pump through a recess which terminates short of saidpump chambers, with the portion of the pump intermediate the innermostend of said recess and saidpump chambers serving as a fulcrum aboutwhich said lever may be actuated.

4. A construction as defined in claim 2 wherein said actuating lever isadapted to pivot about an axis lying in a plane substantially tangent tosaid pump chambers.

5. A construction as defined in claim 1 wherein said valve means includeresilient flap valves which cooperate with inlet and outlet means inresponse to the pressure and suction forces developed by said diaphragmfor controlling the fluid flow.

6. A diaphragm pump formed of a plurality of elements secured togetherin juxtaposed relationship and including a first member having a pumpchamber formed therein, a flexible diaphragm disposed against one faceof said first member and closing one end of said pump chamber, a secondmember disposed against the face of said first member opposite saiddiaphragm and having fluid inlet and outlet means facilitating fluidflow into and from said pump chamber, a third member disposed againstsaid second member and having valve means for controlling the fluid flowthrough said inlet and outlet means, means disposed against the face ofsaid third member remote from said second member and forming an endmember for said pump, and means for actuating said diaphragm, saidactuating means including a lever connected in contact relation to saiddiaphragm and extending laterally therefrom.

7. A construction as defined in claim 6 wherein the first member isprovided with a recess adjacent to said actuating lever and extendingtoward said pump chamber, with the area of said first member betweensaid pump chamber and recess serving as a fulcrum for said actuatinglever.

8. A construction as defined in claim 6 wherein said actuating lever isadapted to pivot about an axis lying in a plane substantially tangent tosaid pump chamber.

9. A construction as defined in claim 6 wherein said diaphragm includesa pair of flexible sheets secured to each other in contact relation witha portion of the actuating lever being interposed therebetween.

10. A construction as defined in claim 6 wherein said third memberincludes openings aligned with portions of said fluid inlet and outletmeans, and resilient portions forming flap valves and cooperating withother portions of said fluid inlet and outlet means, said flap valvesbeing flexible in response to the forces developed by movement of saiddiaphragm to control the direction and sequence of fluid flow.

11. A diaphragm pump having a pump chamber, a flexible diaphragm closingone end of said pump chamber, a diaphragm actuating lever connected incontact relation to said diaphragm, said diaphragm actuating meansextending outwardly from said pump along a plane substantially parallelto said diaphragm and perpendicularly to the axis of said pump. chamber,inlet and outlet means facilitating fluid flow into and from said pumpchamber in response to movement of said diaphragm, and valve means forcontrolling the fluid flow through said inlet and outlet means.

12. In a double-acting diaphragm pump having a pair of pump chambers, adiaphragm disposed between and separating said pump chambers, saiddiaphragm including a pair of flexible sheets secured to each other incontact relation, and an actuating lever interposed between saidflexible sheets and having a portion extending laterally outwardtherefrom.

13. A construction as defined in claim 12 in which the portion of theactuating lever interposed between the flexible sheets is provided withan enlarged end.

References Cited in the file of this patent UNITED STATES PATENTS109,678 Shearer Nov. 29, 1870 1,296,503 Gorrnan Mar. 4, 1919 1,811,557Ove June 23, 1931 2,185,784 Corydon et a1. June 2, 1940 2,382,798 LanganAug. 14, 1945 FOREIGN PATENTS 12,189 Great Britain June 30, 1904 929,832Germany July 4, 1955

